Prathivadhi Bhayankaram Aṇṇan was a Sri Vaishnava acharya, Tamil and Sanskrit scholar, and the composer of the popular Venkateswara Suprabhatam. Born Hasthigirinathar Aṇṇan in the year 1361, he was one of the prominent disciples of , belonged to a distinguished line of "Acharya Puruṣas", amassing followers. Aṇṇan composed many hymns, of which the popular Venkateshwara Suprabhatham, Venkateṣa Stotram, Venkateṣa Prapatti and Venkateṣa Mangaļāṣāsanam are recited daily at the Tirumala Venkateswara Temple at the wee-hours of the day to ritually rouse Venkateshvara. The rendition of the hymns by the singer M S Subbulakshmi is played everyday in millions of households in India and abroad.